- Sodium cyanide-promoted copper-catalysed aerobic oxidative synthesis of esters from aldehydes
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A simple and efficient copper-catalysed procedure for oxidative esterification of aldehydes with alcohols and phenols mediated by sodium cyanide, using air as a clean oxidant, is described. A variety of aromatic aldehydes and structurally different alcohols and phenols reacted efficiently, and the product esters were obtained in good to excellent yields under normal atmospheric and solvent-free conditions.
- Nowrouzi, Najmeh,Abbasi, Mohammad,Bagheri, Maryam
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- Evidence of substituent-induced electronic interplay. Effect of the remote aromatic ring substituent of phenyl benzoates on the sensitivity of the carbonyl unit to electronic effects of phenyl or benzoyl ring substituents
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Carbonyl carbon 13C NMR chemical shifts δC(C=O) measured in this work for a wide set of substituted phenyl benzoates p-Y-C 6H4CO2C6H4-p-X (X = NO2, CN, Cl, Br, H, Me, or MeO; Y = NO2, Cl, H, Me, MeO, or NMe2) have been used as a tool to study substituent effects on the carbonyl unit. The goal of the work was to study the cross-interaction between X and Y in that respect. Both the phenyl substituents X and the benzoyl substituents Y have a reverse effect on δC(C=O). Electron-withdrawing substituents cause shielding while electron-donating ones have an opposite influence, with both inductive and resonance effects being significant. The presence of cross-interaction between X and Y could be clearly verified. Electronic effects of the remote aromatic ring substituents systematically modify the sensitivity of the C=O group to the electronic effects of the phenyl or benzoyl ring substituents. Electron-withdrawing substituents in one ring decrease the sensitivity of δC(C=O) to the substitution of another ring, while electron-donating substituents inversely affect the sensitivity. It is suggested that the results can be explained by substituent-sensitive balance of the contributions of different resonance structures (electron delocalization, Scheme 1).
- Neuvonen, Helmi,Neuvonen, Kari,Pasanen, Paavo
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p. 3794 - 3800
(2007/10/03)
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- Isolation of an inclusion complex of naphthol and its benzoate as an intermediate in the solvent-free benzoylation reaction of naphthol
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A study was performed on isolation of an inclusion complex of naphthol and its benzoate as an intermediate in the solvent-free benzoylation reaction of naphthol. Solvent-free benzoylation reactions were carried out by heating a stirred mixture of phenols or naphthols and benzoyl chloride. The structure of the 2 : 1 inclusion complex of 2,3 naphthalenediol and its p-methylbenzoate was studied by X-ray analysis.
- Nakamatsu, Seiken,Yoshizawa, Kazuhiro,Toyota, Sinji,Toda, Fumio,Matijasic, Ivanka
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p. 2231 - 2234
(2007/10/03)
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- A Novel Synthesis of Phenyl Carboxylates
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The direct synthesis of phenyl carboxylates from phenols and carboxylic acids is reported.The reactions proceeded easily when triphenylphosphine and carbon tetrachloride were used as dehydrating agents in the presence of a tertiary amine at room temperature, thus giving esters in high yields.
- Hashimoto, Shizunobu,Furukawa, Isao
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p. 2227 - 2228
(2007/10/02)
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- The Synthesis of Phenyl Carboxylates from p-Bromophenol and Carboxylic Acid
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The reaction of p-bromophenol with carboxylic acids in the presence of triphenylphosphine and triethylamine proceeded at a high temperature, with the elimination of hydrogen bromide, to give phenyl carboxylates and small amounts of p-bromophenyl carboxylates.
- Hashimoto, Shizunobu,Furukawa, Isao
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p. 2839 - 2840
(2007/10/02)
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